Semiconductor device and method of producing semiconductor device

ABSTRACT

A semiconductor device provided on a semiconductor substrate includes an element region including an element, a moisture-resistant frame surrounding the element region, an insulating layer provided between the moisture-resistant frame and an outer peripheral edge of the semiconductor device and on the semiconductor substrate, a first metal line extending along the outer peripheral edge and provided in the insulating layer, and a groove provided in the insulating layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/793,510, filed on Jul. 7, 2015, which is a continuation of U.S.application Ser. No. 13/463,399, filed on May 3, 2012, which is adivisional of U.S. application Ser. No. 12/053,903, filed on Mar. 24,2008, which claims priority from JP 2007-074424, filed Mar. 22, 2007 andJP 2007-338951, filed Dec. 28, 2007, upon which this patent applicationis based, is hereby incorporated by reference.

TECHNICAL FIELD

The embodiments relate to a semiconductor device and a method ofproducing the same.

BACKGROUND

In the formation of semiconductor devices on a wafer, the number ofeffective chips is determined by the area of the semiconductor devicesand the area of scribe line regions. Consequently, it has been desiredthat the number of effective chips per wafer be increased by reducingthe area of the scribe line regions.

The scribe line regions are regions required for separating a pluralityof semiconductor devices formed on a wafer into chips by laser cuttingor cutting with a dicing saw.

Semiconductor devices each include a circuit pattern region and an outerperipheral region for absorbing cracks formed when the semiconductordevices are separated from each other, the outer peripheral region beingadjacent to the circuit pattern region and a scribe line region. Theouter peripheral region for absorbing cracks due to a chip cuttingextends from an edge of the scribe line region to a moisture-resistantframe-shaped shield disposed within the chip. The moisture-resistantframe-shaped shield is disposed at the boundary between the circuitpattern region and the outer peripheral region. The moisture-resistantframe-shaped shield is provided in order to prevent moisture fromentering the inside of the semiconductor device from the cut surfacesafter the plurality of semiconductor devices formed on the wafer areseparated from each other.

According to a known technique for reducing the outer peripheral regionthat absorbs cracks, a groove for preventing propagation of cracks isprovided on a cover film provided as an uppermost layer of asemiconductor device at a position between an edge of a scribe lineregion and a moisture-resistant frame-shaped shield (see, for example,Japanese Laid-open Patent Application Publication No. 9-199449).According to another technique, a groove extending from the top of asemiconductor device to a substrate is formed at a position between anedge of a scribe line region and a moisture-resistant frame-shapedshield, and the groove is then filled with a metal material (see, forexample, Japanese Unexamined Patent Application Publication No.10-41408).

SUMMARY

An aspect of the embodiments provides a semiconductor device provided ona semiconductor substrate including an element region including anelement, a moisture-resistant frame surrounding the element region, aninsulating layer provided between the moisture-resistant frame and anouter peripheral edge of the semiconductor device and over thesemiconductor substrate, a first metal line extending along the outerperipheral edge and provided in the insulating layer, and a grooveprovided in the insulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a semiconductor device of a firstembodiment;

FIG. 2 is a plan view showing a modification of the semiconductor deviceof the first embodiment;

FIGS. 3A and 3B are cross-sectional views of the semiconductor device ofthe first embodiment and show an advantage of a metal line 2 b in thefirst embodiment;

FIG. 4 is a cross-sectional view showing a modification of thesemiconductor device of the first embodiment and shows a cross sectioncorresponding to an A-A′ cross section of FIG. 1 or FIG. 2;

FIGS. 5A, 5B, and 5C are views illustrating steps of producing asemiconductor device of the first embodiment using an A-A′ cross sectionand a B-B′ cross section of FIG. 1 or FIG. 2;

FIG. 6 includes cross-sectional views showing the A-A′ cross section andthe B-B′ cross section of FIG. 1 or FIG. 2 of the semiconductor deviceof the first embodiment obtained after steps of forming an upper-layerwiring, steps of forming an uppermost-layer wiring, and steps of formingcover films;

FIG. 7 is a cross-sectional view showing an A-A′ cross section of asemiconductor device of a second embodiment;

FIG. 8 is a cross-sectional view showing an A-A′ cross section of asemiconductor device of a third embodiment;

FIG. 9 is a plan view showing a semiconductor device of a fourthembodiment;

FIG. 10 is a plan view showing a modification of the semiconductordevice of the fourth embodiment;

FIG. 11 is a cross-sectional view showing a first example of an A-A′cross-sectional structure of the semiconductor device of the fourthembodiment;

FIG. 12 is a cross-sectional view showing a second example of an A-A′cross-sectional structure of the semiconductor device of the fourthembodiment;

FIG. 13 is a plan view showing a semiconductor device of a fifthembodiment;

FIG. 14 is a cross-sectional view showing an example of an A-A′cross-sectional structure of the semiconductor device of the fifthembodiment;

FIG. 15 is a cross-sectional view showing an A-A′ cross-sectionalstructure of a modification 1 of the semiconductor device of the fifthembodiment;

FIG. 16 is a plan view of a portion where scribe regions 8 b intersecteach other in the case where semiconductor devices of a sixth embodimentare arranged in a matrix shape;

FIG. 17A is a cross-sectional view taken along line C-C′ in FIG. 16;

FIG. 17B is a cross-sectional view taken along line D-D′ in FIG. 16;

FIG. 18 is a view showing a cross section taken along line C-C′ in FIG.16 in a seventh embodiment;

FIGS. 19A to 19F each show a planar shape of a metal patternconstituting a metal line; and

FIG. 19G is a view showing a part of the shape of a mask pattern of amask used for forming a basic metal line.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first embodiment, a second embodiment, a third embodiment, a fourthembodiment, a fifth embodiment, a sixth embodiment, a seventhembodiment, and an eighth embodiment will now be described. The presentinvention is not limited to these embodiments.

First Embodiment

A first embodiment relates to a semiconductor device including, in anouter peripheral region disposed between an element region in which asemiconductor element is provided and a scribe region, a metal lineembedded in grooves which are provided in insulating layers so as tosurround the element region, and in the outer peripheral region, agroove provided in an uppermost insulating film on the metal line.

The first embodiment will now be described with reference to FIGS. 1 to6.

FIG. 1 is a plan view showing a semiconductor device of the firstembodiment. FIG. 1 shows a scribe edge 1, an opening 2 a, a metal line 2b, a moisture-resistant frame-shaped shield 3, an element region 8 a, ascribe region 8 b, and an outer peripheral region 8 c.

The element region 8 a is a region where a pattern of semiconductorcircuits is formed in the semiconductor device.

The scribe region 8 b is a region to be cut when semiconductor devicesformed on a wafer are separated from each other.

The outer peripheral region 8 c is a region that is located between thescribe region 8 b and the element region 8 a and that is disposed so asto surround the element region 8 a in the semiconductor device.

The scribe edge 1 is a boundary between the scribe region 8 b and thesemiconductor device. More specifically, the scribe edge 1 is a boundarybetween the scribe region 8 b and the outer peripheral region 8 c.

The opening 2 a is a groove-shaped opening provided in an uppermostinsulating film included in the semiconductor device. The opening 2 a isdisposed in the outer peripheral region 8 c so as to surround theelement region 8 a in the form of a frame. The opening 2 a is disposedat a position where the opening 2 a two-dimensionally overlaps with themetal line 2 b described below.

The opening 2 a prevents detachment or a crack of the uppermostinsulating film, which is generated when the semiconductor device is cutwith a laser beam or a saw of a dicing machine in the scribe region 8 b,from extending into the element region 8 a.

The reason for this is believed to be as follows. Since the opening 2 ais provided in the uppermost insulating film in the form of a groove,propagation of a crack in the uppermost insulating film from the side ofthe scribe region 8 b can be stopped.

The metal line 2 b is made of the same metal material as wiringsincluded in the semiconductor device. As described below, the metal line2 b is formed by filling grooves, which are provided in insulatinglayers so as to surround the element region 8 a, with the metalmaterial. The insulating layers are insulating layers that separatewiring layers in the semiconductor device.

Here, as described below, the metal line 2 b prevents propagation ofcracks in the insulating layers propagating from the side of the scriberegion 8 b into the element region 8 a. Insulating materials, which donot have elasticity, are easily broken when stress is applied thereto.In contrast, since metal materials have elasticity, a large amount ofstress is required for breaking. Accordingly, it is believed that when ametal material is filled in the grooves in the insulating layers,propagation of cracks in the insulating layers can be prevented.

The moisture-resistant frame-shaped shield 3 is made of the same metalmaterial as wirings included in the semiconductor device. Themoisture-resistant frame-shaped shield 3 is disposed at the boundarybetween the element region 8 a and the outer peripheral region 8 c so asto surround the element region 8 a. As described below, themoisture-resistant frame-shaped shield 3 is composed of all wiringlayers included the semiconductor device. All wirings constituting themoisture-resistant frame-shaped shield 3 are connected by metal plugsthat are provided between the wirings so as to connect upper and lowerwirings and that are embedded in the grooves. As described below, theterm “metal plug” mainly refers to a whole metal material embedded in acontact window, but also refers to a whole metal material embedded in agroove.

The moisture-resistant frame-shaped shield 3 prevents intrusion ofmoisture from the scribe region 8 b to the element region 8 a after thesemiconductor devices are separated from each other by cutting. This isbecause the moisture-resistant frame-shaped shield 3 has a metalwall-like shape surrounding the element region 8 a. It is also believedthat intrusion of moisture into the element region 8 a can be preventedbecause the metal material constituting the moisture-resistantframe-shaped shield 3 reacts with moisture, and thus the moistureremains in the area of the metal material.

FIG. 2 is a plan view showing a modification of the semiconductor deviceof the first embodiment. FIG. 2 shows a scribe edge 1, a C-window shield6 a, a metal line 6 b, a moisture-resistant frame-shaped shield 3, anelement region 8 a, a scribe region 8 b, and an outer peripheral region8 c. The same components as those shown in FIG. 1 are assigned the samereference numerals. Specifically, the scribe edge 1, themoisture-resistant frame-shaped shield 3, the element region 8 a, thescribe region 8 b, and the outer peripheral region 8 c are the same asthose shown in FIG. 1.

The C-window shield 6 a is disposed in the outer peripheral region 8 cand is an opening provided in an uppermost insulating film included inthe semiconductor device. The C-window shield 6 a is composed of fourrectangular grooves each having the same length as that of an edge ofthe element region 8 a. The four grooves are arranged so as to surroundthe element region 8 a. However, the four grooves are discontinuous atfour corners of the element region 8 a. In addition, the four groovesare disposed at positions where the four grooves two-dimensionallyoverlap with the metal line 6 b described below. The C-window shield 6 ahas the same function as that of the opening 2 a.

The metal line 6 b is made of the same metal material as wiringsincluded in the semiconductor device. As described below, the metal line6 b is formed by filling the four rectangular grooves, which areprovided in insulating layers so as to surround the element region 8 a,with the metal material. Specifically, the four grooves do not form aframe shape but are discontinuous at the four corners of the elementregion 8 a. The insulating layers are insulating layers that separatewiring layers in the semiconductor device. An advantage of the presenceof the metal line 6 b is the same as that of the metal line 2 bdescribed above.

The enlarged view indicated by the thin line arrow shows a corner of theelement region 8 a. The structure of this modification can preventstress between each of the insulating layers and the metal material,which is generated when the metal material is elongated by thermalexpansion, from being accumulated between grooves having the metalmaterial therein. The reason for this is as follows. The above-mentionedmetal line 2 b has a planar shape in which the angle is 90 degrees atcorners. Therefore, stress is concentrated on the corners. In contrast,regarding the metal line 6 b, in a direction in which stress is applied,each of the insulating layers and the metal material are in contact witheach other in an edge of the groove having the metal therein. As aresult, the stress can be dispersed.

In addition, as shown in another enlarged view indicated by the thickarrow, by chamfering the corners of the metal line 2 b, stress can besimilarly dispersed at the corners of the metal line 2 b. This isbecause, in a direction in which stress is applied, similarly, each ofthe insulating layers and the metal material are in contact with eachother in a chamfered edge.

FIGS. 3A and 3B are cross-sectional views of a semiconductor device ofthe first embodiment and show an advantage of the metal line 2 b in thefirst embodiment. FIG. 3A is a cross-sectional view showing an A-A′cross section of FIG. 1 and FIG. 2. FIG. 3B is a cross-sectional viewshowing a B-B′ cross section of FIG. 1 and FIG. 2.

FIGS. 3A and 3B show a scribe edge 1, an opening 2 a, a metal line 2 b,a moisture-resistant frame-shaped shield 3, a shallow trench isolation(STI) 10, a source region 11 of a MOS transistor, a drain region 12 ofthe MOS transistor, a gate electrode 13 of the MOS transistor, sidewalls 14, a substrate 15 a, a well 15 b, an insulating film 16, acontact interlayer film 17, a contact interlayer film 18, wiringinterlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31,cover films 32 a and 32 b, wiring-and-plugs 33, 34, 35, 36, 37, 38, and39, a plug 42, a wiring 43, wirings 45 a, 45 b, 45 c, 45 d, 45 e, 45 f,and 45 g, wiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f, and 46 g,a plug 46 h, a wiring 46 i, and arrows 60, 61, 62, and 63.

The scribe edge 1, the opening 2 a, the metal line 2 b, and themoisture-resistant frame-shaped shield 3 are the same as the scribe edge1, the opening 2 a, the metal line 2 b, and the moisture-resistantframe-shaped shield 3 described with reference to FIG. 1.

The B-B′ cross section, which relates to the element region 8 a, willnow be described with reference to FIG. 3B. FIG. 3B shows a bulk portionincluding a MOS transistor and the like, a lower-layer wiring portion,an intermediate-layer wiring portion, an upper-layer wiring portion, anuppermost-layer wiring portion, and a cover film portion.

The bulk portion includes the substrate 15 a, the well 15 b, the STI 10,the MOS transistor, and the insulating film 16.

The substrate 15 a is a semiconductor substrate on which semiconductorelements are formed and has a predetermined conductivity type. The STI10 is an element isolation that electrically isolates the semiconductorelements. The STI 10 is composed of a groove provided betweensemiconductor elements and an insulating material filling the groove.The well 15 b is an impurity region provided from the surface of thesubstrate 15 a toward the inside of the substrate 15 a. An impurity of aconductivity type opposite to that of the MOS transistor formed in thewell 15 b is diffused in the well 15 b.

The source region 11 of the MOS transistor is a region forming a sourceelectrode of the MOS transistor, and is an impurity diffusion region inwhich an impurity of a conductivity type different from the conductivitytype of the substrate 15 a is introduced in the substrate 15 a. Thedrain region 12 of the MOS transistor is a region forming a drainelectrode of the MOS transistor, and is an impurity diffusion regionsimilar to the source region 11. The gate electrode 13 of the MOStransistor is disposed on a gate oxide film provided on the surface ofthe substrate 15 a. The gate electrode 13 is made of, for example,polysilicon, a silicide, a metal, or the like. The drain region 12 andthe source region 11 are disposed at both sides of the gate electrode 13of the MOS transistor. The side walls 14 are provided on the sidewallsof the gate electrode 13 and are composed of, for example, a siliconoxide film. The insulating film 16 is an insulating film provided on theMOS transistor and is composed of, for example, a silicon oxide film.

The lower-layer wiring portion includes the contact interlayer films 17and 18, and four layer units disposed on the contact interlayer films,each of the layer units being composed of a wiring layer and aninterlayer film of the wiring layer.

The contact interlayer films 17 and 18 are sequentially stacked on theinsulating film 16. The contact interlayer films 17 and 18 areinsulating films provided between the MOS transistor and a wiring forbeing electrically in contact with the MOS transistor. Thewiring-and-plug 33 is composed of a wiring that is embedded in a groovein the contact interlayer film 18 and is electrically in contact withthe MOS transistor, and a contact plug embedded in a via in the contactinterlayer film 17. Note that the term “via” refers to an openingprovided so as to penetrate through an insulating film. The term“contact plug” refers to a rod-like metal block that is connected towirings at the top and the bottom thereof so as to electrically connectthe upper wiring to the lower wiring. The wirings and the contact plugare made of a metal material such as copper, or copper and tantalum ortantalum nitride that is provided at the boundary between copper and aninsulating film. Copper is a main component of the wirings. Tantalum ortantalum nitride functions as a diffusion-preventing film that preventscopper from diffusing in the insulating film.

The wiring interlayer films 19 and 20, which are sequentially stacked onthe contact interlayer film 18, are insulating films provided betweenwirings. The wiring-and-plug 34 is composed of a wiring embedded in agroove in the wiring interlayer film 20 and a contact plug embedded in avia in the wiring interlayer film 19. These wiring and contact plug havethe same structures as those described above.

The wiring interlayer films 21 and 22, which are sequentially stacked onthe wiring interlayer film 20, are insulating films provided betweenwirings. The wiring-and-plug 35 is composed of a wiring embedded in agroove in the wiring interlayer film 22 and a contact plug embedded in avia in the wiring interlayer film 21. These wiring and contact plug havethe same structures as those described above.

The wiring interlayer films 23 and 24, which are sequentially stacked onthe wiring interlayer film 22, are insulating films provided betweenwirings. The wiring-and-plug 36 is composed of a wiring embedded in agroove in the wiring interlayer film 24 and a contact plug embedded in avia in the wiring interlayer film 23. These wiring and contact plug havethe same structures as those described above.

The intermediate-layer wiring portion includes the wiring interlayerfilms 25 and 26, and two layer units disposed on the wiring interlayerfilms, each of the layer units being composed of a wiring layer and aninterlayer film of the wiring layer.

The wiring interlayer films 25 and 26, which are sequentially stacked onthe wiring interlayer film 24, are insulating films provided betweenwirings. The wiring-and-plug 37 is composed of a wiring embedded in agroove in the wiring interlayer film 26 and a contact plug embedded in avia in the wiring interlayer film 25. These wiring and contact plug havethe same structures as those described above.

The wiring interlayer films 27 and 28, which are sequentially stacked onthe wiring interlayer film 26, are insulating films provided betweenwirings. The wiring-and-plug 38 is composed of a wiring embedded in agroove in the wiring interlayer film 28 and a contact plug embedded in avia in the wiring interlayer film 27. These wiring and contact plug havethe same structures as those described above.

The upper-layer wiring portion includes the wiring interlayer films 29and 30 and a wiring layer disposed on the wiring interlayer films.

The wiring interlayer films 29 and 30, which are sequentially stacked onthe wiring interlayer film 28, are insulating films provided betweenwirings. The wiring-and-plug 39 is composed of a wiring embedded in agroove in the wiring interlayer film 30 and a contact plug embedded in avia in the wiring interlayer film 29. These wiring and contact plug havethe same structures as those described above.

The uppermost-layer wiring portion includes the wiring interlayer film31, the plug 42, and the wiring 43 composed of a wiring layer disposedon the wiring interlayer film 31 and the plug 42.

The wiring interlayer film 31, which is stacked on the wiring interlayerfilm 30, is an insulating film provided between wirings. The plug 42 iscomposed of a contact plug embedded in a via in the wiring interlayerfilm 31. The contact plug of the plug 42 may be made of copper thesurface of which is covered with titanium nitride. Alternatively, thiscontact plug may be made of tungsten.

The wiring 43 is an uppermost wiring provided on the wiring interlayerfilm 31. The wiring 43 is made of copper or aluminum. When the wiring 43is made of aluminum as shown in the figure, the wiring 43 is formed byetching using a resist patterned by photolithography as a mask.

Although not shown in the figure, when the wiring 43 is made of copper,the wiring 43 is formed by forming a groove in the cover film 32 a andthen embedding copper in the groove.

The cover film portion includes the cover film 32 a and the cover film32 b. The cover film 32 a is an insulating film stacked on the wiring43. The cover film 32 b is an uppermost insulating film stacked on thecover film 32 a.

The A-A′ cross section, which relates to the portion ranging from thescribe region 8 b to the moisture-resistant frame-shaped shield 3, willnow be described with reference to FIG. 3A. FIG. 3A shows the scribeedge 1, the metal line 2 b, the opening 2 a, and the moisture-resistantframe-shaped shield 3.

The moisture-resistant frame-shaped shield 3 is composed ofwiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f, and 46 g, the plug46 h, and the wiring 46 i.

The wiring-and-plug 46 a is composed of a wiring embedded in a groove inthe contact interlayer film 18 and a contact plug embedded in a via inthe contact interlayer film 17. The above via includes not only a normalrectangular via used in the element region 8 a but also a groove-shapedvia. The wiring-and-plug 46 a is connected to the substrate 15 a. Thewiring-and-plug 46 a is made of, for example, copper covered withtantalum or tantalum nitride. Tantalum or tantalum nitride functions asa diffusion-preventing film that prevents copper from diffusing in thecontact interlayer films 17 and 18.

The wiring-and-plug 46 b is composed of a wiring embedded in a groove inthe wiring interlayer film 20 and a contact plug embedded in a via inthe wiring interlayer film 19. The wiring-and-plug 46 b is connected tothe wiring-and-plug 46 a. The wiring-and-plug 46 b is also formed by adual damascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 46 c is composed of a wiring embedded in a groove inthe wiring interlayer film 22 and a contact plug embedded in a via inthe wiring interlayer film 21. The wiring-and-plug 46 c is connected tothe wiring-and-plug 46 b. The wiring-and-plug 46 c is also formed by adual damascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 46 d is composed of a wiring embedded in a groove inthe wiring interlayer film 24 and a contact plug embedded in a via inthe wiring interlayer film 23. The wiring-and-plug 46 d is connected tothe wiring-and-plug 46 c. The wiring-and-plug 46 d is also formed by adual damascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 46 e is composed of a wiring embedded in a groove inthe wiring interlayer film 26 and a contact plug embedded in a via inthe wiring interlayer film 25. The wiring-and-plug 46 e is connected tothe wiring-and-plug 46 d. The wiring-and-plug 46 e is also formed by adual damascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 46 f is composed of a wiring embedded in a groove inthe wiring interlayer film 28 and a contact plug embedded in a via inthe wiring interlayer film 27. The wiring-and-plug 46 f is connected tothe wiring-and-plug 46 e. The wiring-and-plug 46 f is also formed by adual damascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 46 g is composed of a wiring embedded in a groove inthe wiring interlayer film 30 and a contact plug embedded in a via inthe wiring interlayer film 29. The wiring-and-plug 46 g is connected tothe wiring-and-plug 46 f. The wiring-and-plug 46 g is also formed by adual damascene process as in the above-mentioned wiring-and-plug.

The plug 46 h is a contact plug embedded in a via in the wiringinterlayer film 31. The wiring-and-plug 46 h is connected to thewiring-and-plug 46 g. This contact plug may be made of copper coveredwith tantalum or tantalum nitride. Alternatively, this contact plug maybe made of tungsten.

The wiring 46 i is a wiring provided on the wiring interlayer film 31.The wiring 46 i is connected to the plug 46 h. The wiring 46 i is madeof copper or aluminum. When the wiring 46 i is made of aluminum as shownin the figure, the wiring 46 i is formed by etching using a resistpatterned by photolithography as a mask. Although not shown in thefigure, when the wiring 46 i is made of copper, the wiring 46 i isformed by forming a groove in the cover film 32 a and then embeddingcopper in the groove.

The metal line 2 b is composed of the wirings 45 a, 45 b, 45 c, 45 d, 45e, 45 f, and 45 g. The wirings constituting the metal line 2 b do notinclude a wiring disposed at a position corresponding to the plug 46 hand the wiring 46 i forming the moisture-resistant frame-shaped shield3. This is because it is necessary to ensure a certain amount of thedepth of a groove of the opening 2 a described below.

The wiring 45 a is made of a metal material embedded in a groove in thecontact interlayer film 18. The metal material is copper covered withtantalum or tantalum nitride. Tantalum or tantalum nitride functions asa diffusion-preventing film that prevents copper from diffusing in thecontact interlayer film 18.

The wiring 45 b is composed of a wiring embedded in a groove in thewiring interlayer film 20. The wiring 45 b is also formed by a damasceneprocess as in the above-mentioned wiring.

The wiring 45 c supposed of a wiring embedded in a groove in the wiringinterlayer film 22. The wiring 45 c is also formed by a damasceneprocess as in the above-mentioned wiring.

The wiring 45 d is composed of a wiring embedded in a groove in thewiring interlayer film 24. The wiring 45 d is also formed by a damasceneprocess as in the above-mentioned wiring.

The wiring 45 e is composed of a wiring embedded in a groove in thewiring interlayer film 26. The wiring 45 e is also formed by a damasceneprocess as in the above-mentioned wiring.

The wiring 45 f is composed of a wiring embedded in a groove in thewiring interlayer film 28. The wiring 45 f is also formed by a damasceneprocess as in the above-mentioned wiring.

The wiring 45 g is composed of a wiring embedded in a groove in thewiring interlayer film 30. The wiring 45 g is also formed by a damasceneprocess as in the above-mentioned wiring.

The opening 2 a is a groove formed in the cover films 32 a and 32 b. Forexample, as shown in FIG. 3A, the opening 2 a is a groove thatpenetrates through the cover film 32 b and that reaches at a halfwayposition of the cover film 32 a.

Note that the planar position of an edge of the groove constituting theopening 2 a at the side of the element region 8 a is aligned with thatof an edge of the wirings 45 a to 45 g at the side of the element region8 a. However, even if the position of the edge of the wirings 45 a to 45g at the side of the element region 8 a is shifted from the position ofthe edge of the groove constituting the opening 2 a at the side of theelement region 8 a within the range of 1 to 10 μm in the horizontaldirection of the cross-sectional view, an advantage achieved by thepresence of the opening 2 a and the metal line 2 b does not decrease.

The scribe edge 1 is an edge of the outermost periphery of thesemiconductor device.

The advantage of the presence of the opening 2 a and the metal line 2 bin the semiconductor device of the first embodiment will now bedescribed with reference to FIG. 3A.

In FIG. 3A, each of the arrows 60 and 61 shows a propagation state of acrack formed in the scribe edge 1 when the semiconductor device is cutin the scribe region 8 b.

Here, in the semiconductor device, in order to form eight wiring layers,fifteen wiring interlayer films are provided, as shown in FIG. 3B.Accordingly, it is believed that the crack propagates along the wiringinterlayer films as shown by the arrow 60 or 61.

Consequently, it is believed that when the metal line 2 b formed byfilling a groove in each of the wiring interlayer films with a metalmaterial is provided, propagation of the crack in the wiring interlayerfilms can be prevented.

Insulating materials constituting the wiring interlayer films, whichwill be described below, do not have elasticity. Therefore, suchinsulating materials are easily broken when stress is applied thereto.In contrast, metal materials have elasticity, and thus, it is believedthat such metal materials are not broken even when stress is appliedthereto. The reason for this is as follows. When stress due topropagation of cracks is applied to a metal material, the metal materialundergoes elastic deformation, thereby releasing the stress. Inaddition, a stress that exceeds the limit of elastic deformation of ametal material and that results in the metal material being broken islarger than a stress that results in an insulating material beingbroken.

Accordingly, the metal line 2 b provides an advantage of reliablypreventing propagation of cracks in the wiring interlayer films.

Next, in FIG. 3A, the arrow 63 shows a phenomenon in which a crackpropagates from an edge of the opening 2 a unless the metal line 2 b isprovided.

The reason why a crack propagates from an edge of the opening 2 a is asfollows. First, detachment of a cover film that occurs during cutting ofthe semiconductor device in the scribe region 8 b extends. Extension ofthe detachment of the cover film is prevented because the groove of theopening 2 a is provided in the cover film in advance. In this case, aforce from the scribe region 8 b is applied at the side of the elementregion 8 a of the groove of the opening 2 a.

Consequently, the present inventor has found that when the metal line 2b is provided in FIG. 3A, a crack propagating from the edge of theopening 2 a propagates along the metal line 2 b as shown by the arrow62.

This structure is advantageous in that the crack propagating from theedge of the opening 2 a does not reach the moisture-resistantframe-shaped shield 3, and the moisture-resistant frame-shaped shield 3and the element region 8 a are protected by the metal line 2 b.

Accordingly, this structure is advantageous in that propagation ofcracks formed at the side of the element region 8 a of the metal line 2b can also be reliably prevented.

Thus, the semiconductor device of the first embodiment is asemiconductor device having a crack-propagation-preventing structurecomposed of the metal line 2 b and the opening 2 a.

A modification of the semiconductor device of the first embodiment willnow be described with reference to FIG. 4. FIG. 4 is a cross-sectionalview showing a modification of the semiconductor device of the firstembodiment and shows a cross section corresponding to the A-A′ crosssection of FIG. 1 or FIG. 2. FIG. 4 shows a scribe edge 1, an opening 2a, a metal line 2 b, a moisture-resistant frame-shaped shield 3, aninsulating film 16, a contact interlayer film 17, a contact interlayerfilm 18, wiring interlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, and 31, cover films 32 a and 32 b, wirings 45 a, 45 b, 45 c, 45d, 45 e, 45 f, 45 g, and 45 h, wiring-and-plugs 46 a, 46 b, 46 c, 46 d,46 e, 46 f, and 46 g, a plug 46 h, a wiring 46 i, and arrows 60, 61, 62,and 63.

The same components as those shown in FIG. 1 are assigned the samereference numerals. Specifically, the scribe edge 1, the opening 2 a,the metal line 2 b, and the moisture-resistant frame-shaped shield 3 arethe same as the scribe edge 1, the opening 2 a, the metal line 2 b, andthe moisture-resistant frame-shaped shield 3 that are described withreference to FIG. 1. The insulating film 16, the contact interlayer film17, the contact interlayer film 18, the wiring interlayer films 19, 20,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31, and the cover films 32 aand 32 b are also the same as those described with reference to FIG. 1.However, this semiconductor device differs from the above-describedsemiconductor device in that the metal line 2 b is composed of thewirings 45 a, 45 b, 45 c, 45 d, 45 e, 45 f, 45 g, and 45 h. That is,this semiconductor device further includes the wiring 45 h.

The wiring 45 h is a metal wiring that belongs to a wiring layer (i.e.,uppermost wiring layer) to which the wiring 46 i of themoisture-resistant frame-shaped shield 3 also belongs. The wiring 45 his made of aluminum. Accordingly, the wiring 45 h is formed by the samestep as that of forming the wiring 43 using aluminum between the stepsof forming the wiring 43 in the element region 8 a.

The wiring 45 h has a frame shape surrounding the element region 8 b andthe moisture-resistant frame-shaped shield 3. The width of the wiring 45h is larger than the width of the groove of the opening 2 a.

The semiconductor device of the first embodiment does not include awiring corresponding to the wiring 46 i of the moisture-resistantframe-shaped shield 3. This is because, in the case where the wiringcorresponding to the wiring 46 i is made of copper, a phenomenon shouldbe prevented in which copper is exposed and a metal contamination due tocopper occurs in a process apparatus.

In contrast, in this modification of the semiconductor device of thefirst embodiment, since the wiring 45 h is made of aluminum, the problemof the metal contamination does not occur. It is known that even if ametal contamination due to aluminum occurs, the effect thereof isnegligible.

Accordingly, although the cover film 32 a remains between the bottom ofthe opening 2 a and the wiring 45 h in FIG. 4, the opening 2 a may reachthe wiring 45 h.

An advantage of the presence of the opening 2 a and the metal line 2 bin the modification of the semiconductor device of the first embodimentshown in FIG. 4 is as follows.

In FIG. 4, when a crack propagates from the direction shown by the arrow60 or 61, propagation of the crack can be prevented as in the case ofthe metal line 2 b of the semiconductor device of the first embodiment.

As described above, in the case where the metal line 2 b is notprovided, a crack propagates from an edge of the opening 2 a in thedirection shown by the arrow 63.

In the metal line 2 b of the semiconductor device of the firstembodiment, the direction in which the crack propagates is changed tothe direction shown by the arrow 62 because of the presence of thewirings 45 a to 45 g. Thus, propagation of cracks into the elementregion 8 a can be prevented.

In contrast, in the metal line 2 b of the modification of thesemiconductor device of the first embodiment, the metal line 2 bincludes the wiring 45 h, and the width of the wiring 45 h is largerthan the width of the groove of the opening 2 a. Therefore, thisstructure is advantageous in that propagation of a crack in thedirection shown by the arrow 63 can be prevented in the first place.This is because the wiring 45 h made of aluminum has high elasticity.

A method of producing a semiconductor device of the first embodimentwill now be described with reference to FIGS. 5A, 5B, 5C, and 6.

FIGS. 5A, 5B, and 5C are views illustrating steps of producing thesemiconductor device of the first embodiment using an A-A′ cross sectionand a B-B′ cross section of FIG. 1 or FIG. 2. FIG. 6 includes viewsshowing an A-A′ cross section and a B-B′ cross section of FIG. 1 or FIG.2 of the semiconductor device of the first embodiment obtained aftersteps of forming an upper-layer wiring, steps of forming anuppermost-layer wiring, and steps of forming cover films. FIGS. 5A, 5B,5C, and 6 show an opening 2 a, a metal line 2 b, a moisture-resistantframe-shaped shield 3, a STI 10, a source region 11 of a MOS transistor,a drain region 12 of the MOS transistor, a gate electrode 13 of the MOStransistor, side walls 14, a substrate 15 a, a well 15 b, an insulatingfilm 16, a contact interlayer film 17, a contact interlayer film 18,wiring interlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,and 31, cover films 32 a and 32 b, wiring-and-plugs 33, 34, 35, 36, 37,38, and 39, a plug 42, a wiring 43, wirings 45 a, 45 b, 45 c, 45 d, 45e, 45 f, and 45 g, wiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f,and 46 g, a plug 46 h, and a wiring 46 i. The same components as thoseshown in FIGS. 3A and 3B are assigned the same reference numerals.

FIG. 5A shows the A-A′ cross section and the B-B′ cross section of FIG.1 or FIG. 2. FIG. 5A shows a cross section of the semiconductor deviceof the first embodiment obtained after steps of forming a bulk. Thesteps of forming a bulk include steps of forming the MOS transistor by aknown process.

For example, as shown in the B-B′ cross section of FIG. 5A, the STI 10for electrically isolating a semiconductor element is formed on thesubstrate 15 a. Subsequently, an impurity of a conductivity typeopposite to that of the MOS transistor is introduced in the well 15 b byion implantation. A heat treatment is then performed to form the well 15b. A gate insulating film is formed on the surface of the substrate 15a. A silicon oxide film or a high dielectric film is used as the gateinsulating film. Subsequently, polysilicon is deposited on the gateinsulating film, and a photomask having the shape of a gate electrode isthen formed thereon by photolithography. The polysilicon is then etchedby anisotropic etching to form the gate electrode 13. Subsequently, animpurity of a conductivity type the same as the conductivity type of theMOS transistor is introduced in source/drain extension regions by ionimplantation using the gate electrode 13 as a mask. Accordingly, thesource/drain extension regions are formed at both sides of the gateelectrode 13. An insulating film is deposited on the MOS transistor andthen anisotropically etched, thereby forming the side walls 14 on theside walls of the gate electrode 13. An impurity of a conductivity typethe same as the conductivity type of the MOS transistor is introduced insource/drain regions by ion implantation using the gate electrode 13 andthe side walls 14 as a mask. Accordingly, the source/drain regions areformed at both sides of the side walls 14, thus forming a diffusionregion where the source/drain regions are integrated with thesource/drain extension regions. The insulating film 16 is then depositedon the MOS transistor.

On the other hand, in the A-A′ cross section of FIG. 5A, the gateinsulating film and the insulating film 16 are also formed on theportion corresponding to the moisture-resistant frame-shaped shield 3 inthe step of forming the gate insulating film and the step of forming theinsulating film 16, respectively, among the above-described steps.However, no components are formed in other steps. However, a diffusionlayer in which an impurity of a conductivity type the same as theconductivity type of the substrate 15 a is introduced may be formed inthe substrate 15 a located under the wiring-and-plug 46 a included inthe moisture-resistant frame-shaped shield 3 in the step of forming thesource/drain regions of the MOS transistor. This is because the electricpotential of the moisture-resistant frame-shaped shield 3 is stabilized.Furthermore, the gate insulating film and the insulating film 16 arealso formed at the position corresponding to the metal line 2 b in thestep of forming the gate insulating film and the step of forming theinsulating film 16, respectively.

FIG. 5B shows the A-A′ cross section and the B-B′ cross section of FIG.1 or FIG. 2 of the semiconductor device of the first embodiment obtainedafter steps of forming a lower-layer wiring. The steps of forming alower-layer wiring include steps of forming the lower-layer wiringportion by a known process, i.e., a dual damascene process.

For example, in the B-B′ cross section of FIG. 5B, the contactinterlayer film 17 composed of a silicon oxide film and a siliconnitride film, and the contact interlayer film 18 composed of a siliconoxide film are deposited by chemical vapor deposition (CVD).

Subsequently, a groove for forming a wiring connected to the MOStransistor therein is formed in the contact interlayer film 18. A viathat is in contact with the source region 11, the drain region 12, andthe gate electrode 13 of the MOS transistor is then formed in thecontact interlayer film 17. Subsequently, tantalum or tantalum nitrideis deposited inside the via and the groove by CVD. Copper is thendeposited thereon by plating. Copper disposed on the contact interlayerfilm 18 is then removed by chemical mechanical polishing (CMP).

As a result, copper is embedded in the groove and the via to form thewiring-and-plug 33.

On the other hand, in the A-A′ cross section of FIG. 5B, theabove-described steps are performed in the same manner, and thus, thewiring-and-plug 46 a is formed at the position corresponding to themoisture-resistant frame-shaped shield 3. No via is formed in thecontact interlayer film 17 at the position corresponding to the metalline 2 b. Consequently, a plug made of copper is not formed in thecontact interlayer film 17. Accordingly, in the above steps, the wiring45 a is formed in a groove in the contact interlayer film 18 at theposition corresponding to the metal line 2 b.

The wiring interlayer films 19 and 20, the wiring-and-plug 34, thewiring-and-plug 46 b forming the moisture-resistant frame-shaped shield3, and the wiring 45 b forming the metal line 2 b, all of which areshown in FIG. 5B, are formed by the same steps as those described above.

Furthermore, the wiring interlayer films 21, 22, 23, and 24, thewiring-and-plugs 35 and 36, the wiring-and-plugs 46 c and 46 d formingthe moisture-resistant frame-shaped shield 3, and the wirings 45 c and45 d forming the metal line 2 b, all of which are shown in FIG. 5B, areformed by repeating the same steps as those described above.

FIG. 5C shows the A-A′ cross section and the B-B′ cross section of FIG.1 or FIG. 2 of the semiconductor device of the first embodiment obtainedafter steps of forming an intermediate-layer wiring. The steps offorming an intermediate-layer wiring include steps of forming theintermediate-layer wiring portion by a known process, i.e., a dualdamascene process.

Accordingly, the wiring interlayer films 25, 26, 27, and 28, thewiring-and-plugs 37 and 38, the wiring-and-plugs 46 e and 46 f formingthe moisture-resistant frame-shaped shield 3, and the wirings 45 e and45 f forming the metal line 2 b are formed by repeating the same stepsas those described in the steps of forming a lower-layer wiring.

FIG. 6 includes cross-sectional views showing the A-A′ cross section andthe B-B′ cross section of FIG. 1 or FIG. 2 of the semiconductor deviceof the first embodiment obtained after steps of forming an upper-layerwiring, steps of forming an uppermost-layer wiring, and steps of formingcover films.

The steps of forming an upper-layer wiring include steps of forming theupper-layer wiring portion by a known process, i.e., a dual damasceneprocess. Accordingly, the wiring interlayer films 29 and 30, thewiring-and-plug 39, the wiring-and-plug 46 g forming themoisture-resistant frame-shaped shield 3, and the wiring 45 g formingthe metal line 2 b are formed by the same steps as those describedabove.

The steps of forming an uppermost-layer wiring include steps of formingthe uppermost-layer wiring portion by known steps of forming a wiringand a plug.

For example, as shown in the B-B′ cross section of FIG. 6, the wiringinterlayer film 31 composed of a silicon oxide film is deposited by CVD.A via to be connected to the wiring-and-plug 39 is then formed on thewiring interlayer film 31. Subsequently, tungsten is deposited over theentire surface of the wiring interlayer film 31 by sputtering or CVD.Tungsten deposited on the wiring interlayer film 31 is then removed byCMP. Consequently, tungsten is embedded in the via in the wiringinterlayer film 31, thus forming the plug 42 made of tungsten.Subsequently, aluminum is deposited on the wiring interlayer film 31 bysputtering. A resist pattern having a shape of wiring is then formed onaluminum by photolithography. The resist pattern is then anisotropicallyetched to form the wiring 43.

On the other hand, as shown in the A-A′ cross section of FIG. 6, theplug 46 h and the wiring 46 i of the moisture-resistant frame-shapedshield 3 are formed by the same steps as those described above.

An uppermost-layer wiring forming the metal line 2 b is not formed inorder that the bottom of a groove of the opening 2 a described below isnot in contact with the uppermost-layer wiring when the opening 2 a isformed. When an uppermost-layer wiring forming the metal line 2 b isprovided and if the bottom of the groove of the opening 2 a is incontact with the uppermost-layer wiring, the following problem occurs.In the case where the uppermost-layer wiring is made of copper, copperis exposed and a process apparatus may be contaminated with copper inthe step and subsequent steps. In addition, unless the depth of thegroove of the opening 2 a is sufficient, extension of the detachment ofthe cover films 32 a and 32 b cannot be prevented.

In the B-B′ cross section of FIG. 6, the steps of forming cover filmsinclude steps of forming the cover films 32 a and 32 b by depositingsilicon oxide or silicon nitride by CVD. On the other hand, in the A-A′cross section of FIG. 6, after the formation of the cover films 32 a and32 b, a resist pattern having an opening corresponding to the opening 2a is formed on the cover film 32 b by photolithography. Subsequently,the cover films 32 a and 32 b are etched by anisotropic etching to formthe groove of the opening 2 a. Note that the position of an edge of theopening 2 a at the side of the moisture-resistant frame-shaped shield 3is substantially aligned with the position of an edge of the wirings 45a, 45 b, 45 c, 45 d, 45 e, 45 f, and 45 g forming the metal line 2 b atthe side of the moisture-resistant frame-shaped shield 3, when viewed inthe cross-sectional view. This is because a crack propagating from anedge of the opening 2 a propagates along the metal line 2 b as shown bythe arrow 62 in the case where the metal line 2 b is provided.

In the method of producing a semiconductor device of the firstembodiment, the metal line 2 b and the opening 2 a can be easily formedby the same steps as those of forming a semiconductor element andwirings in the element region 8 a. As a result, propagation of cracksfrom the metal line 2 b to the moisture-resistant frame-shaped shield 3can be prevented.

Second Embodiment

A semiconductor device of a second embodiment will now be described withreference to FIG. 7. In the semiconductor device of the secondembodiment, wirings forming the metal line 2 b of the first embodimentare changed to wiring-and-plugs.

FIG. 7 is a cross-sectional view showing an A-A′ cross section of thesemiconductor device of the second embodiment. FIG. 7 shows a scribeedge 1, an opening 2 a, a metal line 2 b, a moisture-resistantframe-shaped shield 3, an insulating film 16, a contact interlayer film17, a contact interlayer film 18, wiring interlayer films 19, 20, 21,22, 23, 24, 25, 26, 27, 28, 29, 30, and 31, and cover films 32 a and 32b.

The same components as those shown in FIGS. 1, 2, 3A, 3B, 5A, 5B, 5C,and 6 are assigned the same reference numerals.

The plan view of the semiconductor device of the second embodiment isthe same as FIG. 1 or FIG. 2. Accordingly, the planar positionalrelationship of the scribe edge 1, the opening 2 a, the metal line 2 b,and moisture-resistant frame-shaped shield 3 is the same as thepositional relationship described with reference to FIG. 1 and FIG. 2.

However, the metal line 2 b shown in FIG. 7 differs from the metal line2 b of the first embodiment in that the metal line 2 b of thisembodiment is composed of wiring-and-plugs 47 a, 47 b, 47 c, 47 d, 47 e,47 f, and 47 g.

The wiring-and-plugs constituting the metal line 2 b do not include awiring disposed at a position corresponding to the plug 46 h and thewiring 46 i forming the moisture-resistant frame-shaped shield 3. Thisis because it is necessary to ensure a certain amount of the depth of agroove of the opening 2 a. As in the semiconductor device of the firstembodiment, the position of an edge of the wiring-and-plugs 47 a, 47 b,47 c, 47 d, 47 e, 47 f, and 47 g at the side of the element region 8 ais aligned with the position of an edge of the groove of the opening 2 aat the side of the element region 8 a.

Each of the wiring-and-plugs 47 a, 47 b, 47 c, 47 d, 47 e, 47 f, and 47g is connected to adjacent wiring-and-plugs and integrated with eachother.

The wiring-and-plug 47 a is composed of a wiring embedded in a groove inthe contact interlayer film 18 and a contact plug embedded in a via inthe contact interlayer film 17. Here, the via includes not only a knownvia used in the element region 8 a but also a groove-shaped via. Theabove wiring and contact plug are made of copper covered with tantalumor tantalum nitride. Tantalum or tantalum nitride functions as adiffusion-preventing film that prevents copper from diffusing in thecontact interlayer films 17 and 18. The wiring-and-plug 47 a is formedtogether with the wiring-and-plug 33 in the element region 8 a by a dualdamascene process.

The wiring-and-plug 47 b is composed of a wiring embedded in a groove inthe wiring interlayer film 20 and a contact plug embedded in a via inthe wiring interlayer film 19. The wiring-and-plug 47 b is formedtogether with the wiring-and-plug 34 in the element region 8 a by a dualdamascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 47 c is composed of a wiring embedded in a groove inthe wiring interlayer film 22 and a contact plug embedded in a via inthe wiring interlayer film 21. The wiring-and-plug 47 c is formedtogether with the wiring-and-plug 35 in the element region 8 a by a dualdamascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 47 d is composed of a wiring embedded in a groove inthe wiring interlayer film 24 and a contact plug embedded in a via inthe wiring interlayer film 23. The wiring-and-plug 47 d is formedtogether with the wiring-and-plug 36 in the element region 8 a by a dualdamascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 47 e is composed of a wiring embedded in a groove inthe wiring interlayer film 26 and a contact plug embedded in a via inthe wiring interlayer film 25. The wiring-and-plug 47 e is formedtogether with the wiring-and-plug 37 in the element region 8 a by a dualdamascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 47 f is composed of a wiring embedded in a groove inthe wiring interlayer film 28 and a contact plug embedded in a via inthe wiring interlayer film 27. The wiring-and-plug 47 f is formedtogether with the wiring-and-plug 38 in the element region 8 a by a dualdamascene process as in the above-mentioned wiring-and-plug.

The wiring-and-plug 47 g is composed of a wiring embedded in a groove inthe wiring interlayer film 30 and a contact plug embedded in a via inthe wiring interlayer film 29. The wiring-and-plug 47 g is formedtogether with the wiring-and-plug 39 in the element region 8 a by a dualdamascene process as in the above-mentioned wiring-and-plug.

Referring to FIG. 3A, it is believed that, in the scribe region 8 b, acrack formed in the scribe edge 1 during cutting of the semiconductordevice propagates along wiring interlayer films as shown by the arrow 60or 61.

Referring to FIG. 7, in the metal line 2 b of the second embodiment, ametal material embedded in a groove or a via provided in all the wiringinterlayer films is present. Accordingly, it is believed that the metalline 2 b of the second embodiment has a higher effect of preventingpropagation of cracks in the wiring interlayer films than that of themetal line 2 b of the first embodiment.

Insulating materials constituting the wiring interlayer films, whichwill be described below, do not have elasticity. Therefore, suchinsulating materials are easily broken when stress is applied thereto.In contrast, metal materials have elasticity, and thus, it is believedthat such metal materials are not broken even when stress is appliedthereto. The reason for this is as follows. Metal materials haveelasticity. Therefore, when stress due to propagation of cracks isapplied to a metal material, the metal material undergoes elasticdeformation, thereby releasing the stress.

Accordingly, the metal line 2 b of the second embodiment has an effectof reliably preventing propagation of cracks in the wiring interlayerfilms.

Thus, the semiconductor device of the second embodiment is asemiconductor device having a crack-propagation-preventing structurecomposed of the metal line 2 b and the opening 2 a.

As described above, the metal line 2 b of the second embodiment can alsobe easily formed by the same steps as those of forming a semiconductorelement and wirings in the element region 8 a.

Third Embodiment

A semiconductor device of a third embodiment will now be described withreference to FIG. 8. In the semiconductor device of the thirdembodiment, the width of wirings constituting a metal line 2 b is large,and the wirings project to the side of the scribe region 8 b.

FIG. 8 is a cross-sectional view showing an A-A′ cross section of thesemiconductor device of the third embodiment. FIG. 8 shows a scribe edge1, an opening 2 a, a metal line 2 b, a moisture-resistant frame-shapedshield 3, an insulating film 16, a contact interlayer film 17, a contactinterlayer film 18, wiring interlayer films 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, and 31, and cover films 32 a and 32 b.

The same components as those shown in FIGS. 1, 2, 3A, 3B, 5A, 5B, 5C,and 6 are assigned the same reference numerals.

The plan view of the semiconductor device of the third embodiment is thesame as FIG. 1 or FIG. 2. Accordingly, the planar positionalrelationship of the scribe edge 1, the opening 2 a, the metal line 2 b,and moisture-resistant frame-shaped shield 3 is the same as thepositional relationship described with reference to FIG. 1 and FIG. 2.

However, the metal line 2 b shown in FIG. 8 differs from the metal line2 b of the first embodiment in that the metal line 2 b is composed ofwirings 48 a, 48 b, 48 c, 48 d, 48 e, 48 f, and 48 g.

The wirings constituting the metal line 2 b do not include a wiringdisposed at a position corresponding to the plug 46 h and the wiring 46i forming the moisture-resistant frame-shaped shield 3. This is becauseit is necessary to ensure a certain amount of the depth of a groove ofthe opening 2 a. As in the semiconductor device of the first embodiment,the position of an edge of the wirings 48 a, 48 b, 48 c, 48 d, 48 e, 48f, and 48 g at the side of the element region 8 a is aligned with theposition of an edge of the groove of the opening 2 a at the side of theelement region 8 a.

The width of each of the wirings 48 a, 48 b, 48 c, 48 d, 48 e, 48 f, and48 g is larger than the width of the groove of the opening 2 a. An edgeof each of the wirings 48 a to 48 g at the side of the scribe region 8 bprojects toward the side of the scribe region 8 b with respect to anedge of the groove of the opening 2 a at the side of the scribe region 8b.

The wiring 48 a is composed of a wiring embedded in a groove in thecontact interlayer film 18. This wiring 48 a is made of copper coveredwith tantalum or tantalum nitride. Tantalum or tantalum nitridefunctions as a diffusion-preventing film that prevents copper fromdiffusing in the contact interlayer film 18. The wiring 48 a is formedtogether with the wiring portion of the wiring-and-plug 33 in theelement region 8 a by a damascene process.

The wiring 48 b is composed of a wiring embedded in a groove in thewiring interlayer film 20. The wiring 48 b is formed together with thewiring portion of the wiring-and-plug 34 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 48 c is composed of a wiring embedded in a groove in thewiring interlayer film 22. The wiring 48 c is formed together with thewiring portion of the wiring-and-plug 35 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 48 d is composed of a wiring embedded in a groove in thewiring interlayer film 24. The wiring 48 d is formed together with thewiring portion of the wiring-and-plug 36 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 48 e is composed of a wiring embedded in a groove in thewiring interlayer film 26. The wiring 48 e is formed together with thewiring portion of the wiring-and-plug 37 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 48 f is composed of a wiring embedded in a groove in thewiring interlayer film 28. The wiring 48 f is formed together with thewiring portion of the wiring-and-plug 38 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 48 g is composed of a wiring embedded in a groove in thewiring interlayer film 30. The wiring 48 g is formed together with thewiring portion of the wiring-and-plug 39 in the element region 8 a by adamascene process as in the above-mentioned wiring.

Referring to FIG. 3A, it is believed that, in the scribe region 8 b, acrack formed in the scribe edge 1 during cutting of the semiconductordevice propagates along wiring interlayer films as shown by the arrow 60or 61.

Consequently, referring to FIG. 8, in the metal line 2 b of the thirdembodiment, a metal material embedded in grooves in the wiringinterlayer films is present. In addition, an edge of the grooves for themetal line 2 b of the third embodiment at the side of the scribe region8 b is located nearer the scribe region 8 b, compared with an edge ofthe grooves for the metal line 2 b of the first embodiment at the sideof the scribe region 8 b. Therefore, it is believed that the metal line2 b of the third embodiment has a higher effect of preventingpropagation of cracks in the wiring interlayer films than the effectachieved by the metal line 2 b of the first embodiment. The reason forthis is as follows. Since the width of the each of the grooves includingthe metal material therein is large and an end of each of the grooves islocated nearer to the scribe region 8 b, propagation of cracks from thescribe region 8 b can be stopped at a position nearer to the scriberegion 8 b.

Accordingly, the metal line 2 b of the third embodiment has an effect ofmore strongly and reliably preventing propagation of cracks in thewiring interlayer films.

Thus, the semiconductor device of the third embodiment is asemiconductor device having a crack-propagation-preventing structurecomposed of the metal line 2 b and the opening 2 a.

As described above, the metal line 2 b of the third embodiment can alsobe easily formed by the same steps as those of forming a semiconductorelement and wirings in the element region 8 a.

Fourth Embodiment

Semiconductor devices of a fourth embodiment will now be described withreference to FIGS. 9, 10, 11, and 12. In the semiconductor devices ofthe fourth embodiment, a metal line 4 is further provided between ametal line 2 b and a scribe region 8 b.

FIG. 9 is a plan view showing a semiconductor device of the fourthembodiment. FIG. 9 shows a scribe edge 1, an opening 2 a, a metal line 2b, a moisture-resistant frame-shaped shield 3, the metal line 4, theelement region 8 a, the scribe region 8 b, and an outer peripheralregion 8 c. The same components as those shown in FIG. 1 or FIG. 2 areassigned the same reference numerals.

Accordingly, the description and the arrangement of the scribe edge 1,the opening 2 a, the metal line 2 b, the moisture-resistant frame-shapedshield 3, the element region 8 a, the scribe region 8 b, and the outerperipheral region 8 c are the same as the description and thearrangement in FIG. 1 or FIG. 2.

The metal line 4 is disposed between the opening 2 a and the metal line2 b provided thereunder and the scribe edge 1 in plan view so as tosurround the element region 8 a. The metal line 4 is composed of a metalwiring having a certain width and forms a continuous frame. As describedbelow, the metal line 4 is composed of a metal material embedded ingrooves in a plurality of wiring interlayer films. That is, each of thegrooves also has a continuous frame shape.

FIG. 10 is a plan view showing a modification of the semiconductordevice of the fourth embodiment. FIG. 10 shows a scribe edge 1, anopening 2 a, a metal line 2 b, a moisture-resistant frame-shaped shield3, a metal line 7, the element region 8 a, the scribe region 8 b, and anouter peripheral region 8 c. The same components as those shown in FIG.1 or FIG. 2 are assigned the same reference numerals.

Accordingly, the description and the arrangement of the scribe edge 1,the opening 2 a, the metal line 2 b, the moisture-resistant frame-shapedshield 3, the element region 8 a, the scribe region 8 b, and the outerperipheral region 8 c are the same as the description and thearrangement in FIG. 1 or FIG. 2.

The metal line 7 is disposed between the opening 2 a and the metal line2 b provided thereunder and the scribe edge 1 in plan view so as tosurround the element region 8 a. The metal line 7 is composed of a metalwiring having a certain width and a certain length and is arranged so asto form a discontinuous frame. As described below, the metal line 7 iscomposed of a metal material embedded in grooves in a plurality ofwiring interlayer films. That is, each of the grooves also has a certainwidth and a certain length and arranged so as to form a continuousframe.

FIG. 11 is a cross-sectional view showing a first example of an A-A′cross-sectional structure of the semiconductor device of the fourthembodiment. FIG. 11 shows a scribe edge 1, an opening 2 a, the metalline 2 b, the moisture-resistant frame-shaped shield 3, a metal line 4or 7, an insulating film 16, a contact interlayer film 17, a contactinterlayer film 18, wiring interlayer films 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, and 31, and cover films 32 a and 32 b.

The same components as those shown in FIGS. 1, 2, 3A, 3B, 5A, 5B, 5C,and 6 are assigned the same reference numerals. Accordingly, thestructures of the wirings 45 a, 45 b, 45 c, 45 d, 45 e, 45 f, and 45 gconstituting the metal line 2 b are the same as those shown in FIG. 3A.

The cross-sectional view shown by FIG. 11 differs from thecross-sectional view showing the A-A′ cross section of the semiconductordevice of the first embodiment shown by FIG. 3A in that the metal line 4or 7 is further provided.

The metal line 4 or 7 shown in FIG. 11 is composed of wirings 51 a, 51b, 51 c, 51 d, 51 e, 51 f, and 51 g.

The wirings constituting the metal line 4 or 7 do not include a wiringdisposed at a position corresponding to the plug 46 h and the wiring 46i forming the moisture-resistant frame-shaped shield 3. This is becauseit is necessary to ensure a certain amount of the depth of a groove ofthe opening 2 a. The wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51g are disposed between the scribe edge 1 and the metal line 2 b.

Each of the wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51 gpreferably has the same width as that of each of the wiringsconstituting the metal line 2 b. However, the width of the wirings 51 ato 51 g is not particularly limited as long as the wirings 51 a to 51 gdo not project to the scribe region 8 b.

The wiring 51 a is composed of a wiring embedded in a groove in thecontact interlayer film 18. This wiring 51 a is made of copper coveredwith tantalum or tantalum nitride. Tantalum or tantalum nitridefunctions as a diffusion-preventing film that prevents copper fromdiffusing in the contact interlayer film 18. The wiring 51 a is formedtogether with the wiring portion of the wiring-and-plug 33 in theelement region 8 a by a damascene process.

The wiring 51 b is composed of a wiring embedded in a groove in thewiring interlayer film 20. The wiring 51 b is formed together with thewiring portion of the wiring-and-plug 34 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 51 c is composed of a wiring embedded in a groove in thewiring interlayer film 22. The wiring 51 c is formed together with thewiring portion of the wiring-and-plug 35 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 51 d is composed of a wiring embedded in a groove in thewiring interlayer film 24. The wiring 51 d is formed together with thewiring portion of the wiring-and-plug 36 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 51 e is composed of a wiring embedded in a groove in thewiring interlayer film 26. The wiring 51 e is formed together with thewiring portion of the wiring-and-plug 37 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 51 f is composed of a wiring embedded in a groove in thewiring interlayer film 28. The wiring 51 f is formed together with thewiring portion of the wiring-and-plug 38 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 51 g is composed of a wiring embedded in a groove in thewiring interlayer film 30. The wiring 51 g is formed together with thewiring portion of the wiring-and-plug 39 in the element region 8 a by adamascene process as in the above-mentioned wiring.

FIG. 12 is a cross-sectional view showing a second example of an A-A′cross-sectional structure of the semiconductor device of the fourthembodiment. FIG. 12 shows a scribe edge 1, an opening 2 a, the metalline 2 b, the moisture-resistant frame-shaped shield 3, a metal line 4or 7, an insulating film 16, a contact interlayer film 17, a contactinterlayer film 18, wiring interlayer films 19, 20, 21, 22, 23, 24, 25,26, 27, 28, 29, 30, and 31, and cover films 32 a and 32 b.

The same components as those shown in FIGS. 1, 2, 3A, 3B, 5A, 5B, 5C, 6,and 7 are assigned the same reference numerals. Accordingly, thestructures of the wiring-and-plugs 47 a, 47 b, 47 c, 47 d, 47 e, 47 f,and 47 g constituting the metal line 2 b are the same as those shown inFIG. 7.

The cross-sectional view shown by FIG. 12 differs from thecross-sectional view showing the A-A′ cross section of the semiconductordevice of the second embodiment shown by FIG. 7 in that the metal line 4or 7 is further provided.

The metal line 4 or 7 shown in FIG. 12 is composed of wirings 51 a, 51b, 51 c, 51 d, 51 e, 51 f, and 51 g.

The wirings constituting the metal line 4 or 7 do not include a wiringdisposed at a position corresponding to the plug 46 h and the wiring 46i forming the moisture-resistant frame-shaped shield 3. This is becauseit is necessary to ensure a certain amount of the depth of a groove ofthe opening 2 a. The wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51g are disposed between the scribe edge 1 and the metal line 2 b.

Each of the wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51 gpreferably has the same width as that of each of the wiringsconstituting the metal line 2 b. However, the width of the wirings 51 ato 51 g is not particularly limited as long as the wirings 51 a to 51 gdo not project to the scribe region 8 b.

The wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51 g are the same asthose described in FIG. 11.

Referring to FIG. 3A, it is believed that, in the scribe region 8 b, acrack formed in the scribe edge 1 during cutting of the semiconductordevice propagates along wiring interlayer films as shown by the arrow 60or 61.

Accordingly, the reason why the portion of the metal line 2 b of thefourth embodiment has an effect of preventing propagation of cracks inthe wiring interlayer films is the same as that described in the firstembodiment or the second embodiment.

On the other hand, the metal line 4 or 7 of the fourth embodiment has aneffect of reducing the number of cracks propagating from the scriberegion 8 b. Although the metal line 4 or 7 is not provided in all thewiring interlayer films, in the wiring interlayer films including thewirings 51 a to 51 g constituting the metal line 4 or 7, the metal line4 or 7 has an effect of preventing propagation of cracks. This isbecause the metal line 4 or 7 has the same effect as that of the metalline 2 b. Furthermore, when cracks propagate through the wiringinterlayer films disposed between the wirings 51 a to 51 g constitutingthe metal line 4 or 7, the metal line 4 or 7 has an effect of limitingthe dimension of the cracks. This is because the wirings 51 a to 51 greinforce the wiring interlayer films.

Accordingly, the metal line 2 b and the metal line 4 or 7 of the fourthembodiment has an effect of more strongly and reliably preventingpropagation of cracks in the wiring interlayer films.

Thus, the semiconductor device of the fourth embodiment is asemiconductor device having a crack-propagation-preventing structurecomposed of the metal line 2 b, the metal line 4 or 7, and the opening 2a.

As described above, the metal line 2 b and the metal line 4 or 7 of thefourth embodiment can also be easily formed by the same steps as thoseof forming a semiconductor element and wirings in the element region 8a.

Fifth Embodiment

A semiconductor device of a fifth embodiment and modifications thereofwill now be described with reference to FIGS. 13, 14, and 15. In thesemiconductor device of the fifth embodiment, a metal line 5 is furtherprovided between a metal line 2 b and a moisture-resistant frame-shapedshield 3.

FIG. 13 is a plan view showing the semiconductor device according to thefifth embodiment. FIG. 13 shows a scribe edge 1, an opening 2 a, a metalline 2 b, a moisture-resistant frame-shaped shield 3, a metal line 4, ametal line 5, the element region 8 a, the scribe region 8 b, and anouter peripheral region 8 c. The same components as those shown in FIG.1, FIG. 2, or FIG. 9 are assigned the same reference numerals.

Accordingly, the description and the arrangement of the scribe edge 1,the opening 2 a, the metal line 2 b, the moisture-resistant frame-shapedshield 3, the metal line 4, the element region 8 a, the scribe region 8b, and the outer peripheral region 8 c are the same as the descriptionand the arrangement in FIG. 1, FIG. 2, or FIG. 9.

The metal line 5 is disposed between the opening 2 a and the metal line2 b provided thereunder and the moisture-resistant frame-shaped shield 3in plan view so as to surround the element region 8 a. The metal line 5is composed of a metal wiring having a certain width and forms acontinuous frame. As described below, the metal line 5 is composed of ametal material embedded in grooves in a plurality of wiring interlayerfilms. That is, each of the grooves also has a continuous frame shape.

FIG. 14 is a cross-sectional view showing an example of an A-A′cross-sectional structure of the semiconductor device of the fifthembodiment. FIG. 14 shows a scribe edge 1, an opening 2 a, the metalline 2 b, the moisture-resistant frame-shaped shield 3, a metal line 4,a metal line 5, an insulating film 16, a contact interlayer film 17, acontact interlayer film 18, wiring interlayer films 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29, 30, and 31, and cover films 32 a and 32 b.

The same components as those shown in FIGS. 1, 2, 3A, 3B, 5A, 5B, 5C, 6,and 11 are assigned the same reference numerals. Accordingly, thestructures of the wirings 45 a, 45 b, 45 c, 45 d, 45 e, 45 f, and 45 gconstituting the metal line 2 b are the same as those shown in FIG. 3A.The structures of the wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51g constituting the metal line 4 are also the same as those shown in FIG.11.

The cross-sectional view shown by FIG. 14 differs from thecross-sectional view showing the A-A′ cross section of the semiconductordevice of the fourth embodiment shown by FIG. 11 in that the metal line5 is further provided.

The metal line 5 shown in FIG. 14 is composed of wirings 52 a, 52 b, 52c, 52 d, 52 e, 52 f, and 52 g.

The wirings constituting the metal line 5 do not include a wiringdisposed at a position corresponding to the plug 46 h and the wiring 46i forming the moisture-resistant frame-shaped shield 3. This is becauseit is necessary to ensure a certain amount of the depth of a groove ofthe opening 2 a. The wirings 52 a, 52 b, 52 c, 52 d, 52 e, 52 f, and 52g are disposed between the metal line 2 b and the moisture-resistantframe-shaped shield 3.

Each of the wirings 52 a, 52 b, 52 c, 52 d, 52 e, 52 f, and 52 gpreferably has the same width as that of each of the wiringsconstituting the metal line 2 b. However, the width of the wirings 52 ato 52 g is not particularly limited as long as the wirings 52 a to 52 gare not in contact with the metal line 2 b and the moisture-resistantframe-shaped shield 3.

The wiring 52 a is composed of a wiring embedded in a groove in thecontact interlayer film 18. This wiring 52 a is made of copper coveredwith tantalum or tantalum nitride. Tantalum or tantalum nitridefunctions as a diffusion-preventing film that prevents copper fromdiffusing in the contact interlayer film 18. The wiring 52 a is formedtogether with the wiring portion of the wiring-and-plug 33 in theelement region 8 a by a damascene process.

The wiring 52 b is composed of a wiring embedded in a groove in thewiring interlayer film 20. The wiring 52 b is formed together with thewiring portion of the wiring-and-plug 34 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 52 c is composed of a wiring embedded in a groove in thewiring interlayer film 22. The wiring 52 c is formed together with thewiring portion of the wiring-and-plug 35 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 52 d is composed of a wiring embedded in a groove in thewiring interlayer film 24. The wiring 52 d is formed together with thewiring portion of the wiring-and-plug 36 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 52 e is composed of a wiring embedded in a groove in thewiring interlayer film 26. The wiring 52 e is formed together with thewiring portion of the wiring-and-plug 37 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 52 f is composed of a wiring embedded in a groove in thewiring interlayer film 28. The wiring 52 f is formed together with thewiring portion of the wiring-and-plug 38 in the element region 8 a by adamascene process as in the above-mentioned wiring.

The wiring 52 g is composed of a wiring embedded in a groove in thewiring interlayer film 30. The wiring 52 g is formed together with thewiring portion of the wiring-and-plug 39 in the element region 8 a by adamascene process as in the above-mentioned wiring.

Referring to FIG. 3A, it is believed that, in the scribe region 8 b, acrack formed in the scribe edge 1 during cutting of the semiconductordevice propagates along wiring interlayer films as shown by the arrow 60or 61.

Accordingly, the reason why the portion of the metal line 2 b of thefifth embodiment has an effect of preventing propagation of cracks inthe wiring interlayer films is the same as that described in the firstembodiment or the second embodiment.

In addition, the metal line 4 of the fifth embodiment has an effect ofdecreasing the number of cracks propagating from the scribe region 8 b.The reason for this is the same as that described in the fourthembodiment.

Referring to FIG. 3A again, the present inventor has found that a crackformed at an edge of the opening 2 a propagates in the direction shownby the arrow 62. However, the crack may propagate in the direction shownby the arrow 63 in some cases.

Consequently, it is believed that, when the wirings 52 a to 52 gconstituting the metal line 5 of the fifth embodiment are provided, evenin the case where a crack propagates in the direction shown by the arrow63, propagation of the crack can be prevented.

This is because since the wirings 52 a to 52 g constituting the metalline 5 are embedded in the grooves of wiring interlayer films,propagation of a crack in the wiring interlayer films can be prevented.More specifically, the wirings 52 a to 52 g, which are made of a metalmaterial, have elasticity. Accordingly, when stress due to propagationof a crack is applied to the metal material, the metal materialundergoes elastic deformation, thereby releasing the stress.Furthermore, since the wirings 52 a to 52 g are made of a metal materialand have elasticity, it is believed that a large stress is required forbreaking the wirings 52 a to 52 g.

Accordingly, the metal line 2 b, the metal line 4, and the metal line 5of the fifth embodiment has an effect of more strongly preventingpropagation of cracks in the wiring interlayer films.

Thus, the semiconductor device of the fifth embodiment is asemiconductor device having a crack-propagation-preventing structurecomposed of the metal line 2 b, the metal line 4, the metal line 5, andthe opening 2 a.

As described above, the metal line 2 b, the metal line 4, and the metalline 5 of the fifth embodiment can also be easily formed by the samesteps as those of forming a semiconductor element and wirings in theelement region 8 a.

FIG. 15 is a cross-sectional view showing an A-A′ cross-sectionalstructure of a modification 1 of the semiconductor device of the fifthembodiment. FIG. 15 shows a scribe edge 1, an opening 2 a, a metal line9, a moisture-resistant frame-shaped shield 3, a metal line 4, aninsulating film 16, a contact interlayer film 17, a contact interlayerfilm 18, wiring interlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, and 31, and cover films 32 a and 32 b.

The same components as those shown in FIGS. 1, 2, 3A, 3B, 5A, 5B, 5C, 6,11, and 14 are assigned the same reference numerals. Accordingly, thestructures of the wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51 gconstituting the metal line 4 are the same as those shown in FIG. 11.The structures of the wirings 51 a, 51 b, 51 c, 51 d, 51 e, 51 f, and 51g constituting the metal line 4 are also the same as those shown in FIG.11.

The cross-sectional view shown by FIG. 15 differs from thecross-sectional view showing the A-A′ cross section of the semiconductordevice of the fifth embodiment shown by FIG. 11 in that the metal line 2b and the metal line 5 are integrated to form a metal line 9.

The metal line 9 shown in FIG. 15 is composed of wirings 53 a, 53 b, 53c, 53 d, 53 e, 53 f, and 53 g.

The wirings constituting the metal line 9 do not include a wiringdisposed at a position corresponding to the plug 46 h and the wiring 46i forming the moisture-resistant frame-shaped shield 3. This is becauseit is necessary to ensure a certain amount of the depth of a groove ofthe opening 2 a. The wirings 53 a, 53 b, 53 c, 53 d, 53 e, 53 f, and 53g are disposed between the metal line 4 and the moisture-resistantframe-shaped shield 3.

The wirings 53 a, 53 b, 53 c, 53 d, 53 e, 53 f, and 53 g are metalwirings each having a width that two-dimensionally extends from aposition overlapping with the opening 2 a to the metal line 5 shown inFIG. 14. The wirings 53 a, 53 b, 53 c, 53 d, 53 e, 53 f, and 53 g maytwo-dimensionally extend from a position below the opening 2 a to aposition where the wirings 53 a to 53 g are not in contact with themoisture-resistant frame-shaped shield 3.

Referring to FIG. 3A, it is believed that a crack formed in the scribeedge 1 during cutting of the semiconductor device propagates alongwiring interlayer films as shown by the arrow 60 or 61.

The reason why the metal line 4 of the fifth embodiment has an effect ofreducing the number of cracks propagating from the scribe region 8 b isthe same that described in the fourth embodiment.

Referring to FIG. 3A again, the present inventor has found that a crackformed at an edge of the opening 2 a propagates in the direction shownby the arrow 62. However, the crack may propagate in the direction shownby the arrow 63 in some cases.

Consequently, it is believed that, when the wirings 53 a to 53 gconstituting the metal line 9 of the modification 1 of the fifthembodiment are provided, even in the case where a crack propagates inthe direction shown by the arrow 63, propagation of the crack can beprevented.

This is because since the wirings 53 a to 53 g constituting the metalline 9 are provided in the grooves of wiring interlayer films,propagation of a crack in the wiring interlayer films can be prevented.Furthermore, since the wirings 53 a to 53 g are made of a metal materialand have elasticity, it is believed that a large stress is required forbreaking the wirings 53 a to 53 g.

Accordingly, the metal line 4 and the metal line 9 of the modification 1of the fifth embodiment has an effect of more strongly preventingpropagation of cracks in the wiring interlayer films.

Thus, the modification 1 of the semiconductor device of the fifthembodiment is a semiconductor device having acrack-propagation-preventing structure composed of the metal line 4, themetal line 9, and the opening 2 a.

As described above, the metal line 4 and the metal line 9 of themodification 1 of the fifth embodiment can also be easily formed by thesame steps as those of forming a semiconductor element and wirings inthe element region 8 a.

A modification 2 of the semiconductor device of the fifth embodimentwill now be described. The modification 2 of the semiconductor device ofthe fifth embodiment is an example in which the metal line 4 and themetal line 9 in FIG. 15 are formed as an integrated metal line. Morespecifically, the modification 2 of the semiconductor device of thefifth embodiment is an example in which each of the wirings 51 a to 51 gconstituting the metal line 4 and each of the wirings 53 a to 53 gconstituting the metal line 9 are integrally formed.

That is, the integrated metal line, which is formed so that the metalline 4 and the metal line 9 are integrated with each other, is disposedbetween the scribe edge 1 and the moisture-resistant frame-shaped shield3. The width of the integrated metal line is not particularly limited aslong as the integrated metal line is disposed between the scribe edge 1and the moisture-resistant frame-shaped shield 3.

As described above, the metal line 4 and the metal line 9 of themodification 2 of the fifth embodiment can also be easily formed by thesame steps as those of forming a semiconductor element and wirings inthe element region 8 a.

In the case where the metal line 4 and the metal line 9 are furtherintegrally formed in FIG. 15, the effect of preventing propagation ofcracks due to the presence of the metal line 4, which has been describedin the fourth embodiment, is added to the effect of preventingpropagation of cracks due to the presence of the metal line 9.

Sixth Embodiment

In the semiconductor devices described in the first embodiment to thefifth embodiment, patterns except for the metal line 4, which isdisposed in the scribe region 8 b located between an opening 2 aprovided in cover films 32 a and 32 b of a target semiconductor deviceand an opening 2 a of another semiconductor device adjacent to thetarget semiconductor device, are not considered from the standpoint offormation of cracks. However, when process check monitor (PCM) patternsare provided in the scribe region 8 b, cracks can be intensively formednear the PCM patterns. In view of this problem, a semiconductor deviceof a sixth embodiment includes patterns that are arranged so as toprevent propagation of cracks with paying attention to the presence ofPCM patterns.

A sixth embodiment will now be described with reference to FIG. 16. FIG.16 is a plan view of a portion where scribe regions 8 b intersect eachother in the case where semiconductor devices of the sixth embodimentare arranged in a matrix shape. In FIG. 16, PCM patterns 80, a PCMpattern 81, a metal line 64 a, and a metal line 64 b are arranged in ascribe region 8 b that is disposed between semiconductor devices andthat extends in the horizontal direction. In addition, in FIG. 16, PCMpatterns 82 are arranged in a scribe region 8 b that is disposed betweensemiconductor devices and that extends in the vertical direction.Furthermore, a moisture-resistant frame-shaped shield 3 and an opening 2a are arranged in an outer peripheral region 8 c. Each of thesemiconductor devices of the sixth embodiment includes an element region8 a and an outer peripheral region 8 c. The scribe region 8 b is an arealocated between scribe edges 1. Note that a metal line 2 b is notarranged in the outer peripheral region 8 c.

The element region 8 a, the scribe region 8 b, the outer peripheralregion 8 c, the opening 2 a, and the moisture-resistant frame-shapedshield 3 are the same as those described in the first embodiment.Therefore, a description of these components is omitted.

Each of the PCM patterns 80, 81, and 82 is composed of two or morepatterns that are simultaneously formed with two or more patterns amongpatterns constituting an element provided in the element region 8 a.These PCM patterns 80, 81, and 82 are patterns used for checking thestate of positional alignment of patterns constituting the element. Eachof the PCM patterns 80, 81, and 82 involves a forbidden region whereother patterns cannot be arranged, the forbidden region being locatedwithin a predetermined distance from the PCM patterns 80, 81, and 82.The reason for this is as follows. When the state of positionalalignment of patterns is checked with a laser beam using the PCMpatterns 80, 81, and 82, if other patterns are arranged, laser beamlight reflected from the other patterns and laser beam light reflectedfrom the patterns constituting the PCM patterns 80, 81, and 82 mayinterfere with each other. In such a case, the state of positionalalignment of patterns constituting the PCM patterns 80, 81, and 82cannot be accurately detected.

Each of the PCM patterns 80 is composed of four long rectangularpatterns 65 a, four long rectangular patterns 65 b, and a rectangularpattern 65 c. The four long rectangular patterns 65 a are arrangedinside the rectangular pattern 65 c in the form of a rectangle so as tobe disposed at the center of the rectangular pattern 65 c. Each of therectangular patterns 65 a constitutes each side of the rectangle. Thefour long rectangular patterns 65 b are arranged inside the rectangularpattern 65 c in the form of a rectangle so as to be disposed around thecenter of the rectangular pattern 65 c. Each of the rectangular patterns65 b constitutes each side of the rectangle. The rectangle formed by therectangular patterns 65 a is smaller than the rectangle formed by therectangular patterns 65 b and is arranged inside the rectangle formed bythe rectangular patterns 65 b.

The PCM patterns 80 are arranged in the scribe region 8 b as a unitcomposed of two rows and eight columns along the side of the scriberegion 8 b disposed in the horizontal direction of FIG. 16. The width ofthe unit of the PCM pattern 80 in the column direction is, for example,about 90% of the width of the scribe region 8 b. Accordingly, when thesemiconductor devices are cut in the scribe region 8 b, a cutting bladeis brought into contact with the rectangular patterns 65 a, 65 b, and 65c and the PCM patterns 80 are broken, thus forming cracks. In this case,the positions where the cracks are formed are close to themoisture-resistant frame-shaped shield 3.

The PCM pattern 81 is composed of a rectangular pattern 66 a and aplurality of rectangular patterns 66 b. The rectangular pattern 66 a isa pattern surrounded by short sides and long sides. The rectangularpatterns 66 b are long patterns. The rectangular patterns 66 b areincluded in the rectangular pattern 66 a and arranged at predeterminedintervals so as to be parallel with the short sides of the rectangularpattern 66 a. The PCM pattern 81 is arranged in the scribe region 8 balong the side of the scribe region 8 b disposed in the horizontaldirection of FIG. 16. The width of the PCM pattern 81 is, for example,about 70% of the width of the scribe region 8 b. Accordingly, when thesemiconductor devices are cut in the scribe region 8 b, a cutting bladeis brought into contact with the rectangular patterns 66 a and 66 b andthe PCM pattern 81 is broken, thus forming cracks. In this case, thepositions where the cracks are formed are distant from themoisture-resistant frame-shaped shield 3.

Each of the PCM patterns 82 is composed of a rectangular pattern 67 a, aplurality of rectangular patterns 67 b, and a plurality of rectangularpatterns 67 c. The rectangular pattern 67 a is a square pattern. Therectangular patterns 67 b are long patterns and arranged atpredetermined intervals so as to sandwich the center of the rectangularpattern 67 a and to be parallel with the right side and the left side ofthe rectangular pattern 67 a. The rectangular patterns 67 c are longpatterns and arranged at predetermined intervals so as to sandwich thecenter of the rectangular pattern 67 a and to be parallel with the upperside and the lower side of the rectangular pattern 67 a. Each of the PCMpatterns 82 are arranged in the scribe region 8 b along the side of thescribe region 8 b disposed in the vertical direction of FIG. 16. Thewidth of the PCM pattern 82 is, for example, about 80% of the width ofthe scribe region 8 b. Accordingly, when the semiconductor devices arecut in the scribe region 8 b, a cutting blade is brought into contactwith the rectangular patterns 67 a, 67 b, and 67 c and the PCM patterns82 are broken, thus forming cracks. In this case, the positions wherethe cracks are formed are distant from the moisture-resistantframe-shaped shield 3, compared with the positions where the cracks areformed in the case of the PCM patterns 80.

The metal line 64 a is composed of two long rectangular patternsdisposed at both sides of the PCM patterns 80 along one row, i.e., alongeight PCM patterns 80, in the unit of the PCM patterns 80. A part of themetal line 64 a disposed between the moisture-resistant frame-shapedshield 3 and the PCM patterns 80 belongs to the outer peripheral region8 c. Specifically, the metal line 64 a does not include patternsarranged in the column direction of the PCM patterns 80. The metal line64 a is arranged in areas other than the forbidden region of the PCMpatterns 80.

The metal line 64 a can prevent propagation of a crack formed when thePCM patterns 80 are broken immediately after the formation of the crack.This is because the propagation of the crack is blocked by metalpatterns constituting the metal line 64 a. The metal patterns will bedescribed below in detail with reference to FIGS. 17A and 17B. The metalpatterns have elasticity. Therefore, when stress due to the propagationof a crack is applied to the metal patterns, the metal patterns undergoelastic deformation, thereby releasing the stress.

The metal line 64 b is a strip-shaped pattern with a small width thatsurrounds one row, i.e., eight PCM patterns 80, in the unit of the PCMpatterns 80 so as to form a rectangle. A part of the metal line 64 bdisposed between the moisture-resistant frame-shaped shield 3 and thePCM patterns 80 belongs to the outer peripheral region 8 c. The metalline 64 b is arranged in areas other than the forbidden region of thePCM patterns 80.

As shown in the enlarged view in FIG. 16, the metal line 64 b has adiscontinuous shape at corners of the metal line 64 b, and a space isprovided between two adjacent patterns of the metal line 64 b. Thereason for this is as follows. The pattern constituting the metal line64 b is fine. Therefore, if such a space is not provided at a corner ofthe metal line 64 b, a rounded portion is formed at the corner of themetal line 64 b because of a property of a photolithographic methodwhich is employed for forming the metal line 64 b. As a result, thecorner portion of the metal line 64 b is disposed in a forbidden regionof the PCM patterns 80. In this case, a function of detecting thepositional alignment of the PCM patterns 80 is degraded.

The metal line 64 b can prevent propagation of a crack formed when thePCM patterns 80 are broken immediately after the formation of the crackas in the metal line 64 a.

In FIG. 16, the metal line 64 a is arranged for the upper row of theunit of the PCM patterns 80, and the metal line 64 b is arranged for thelower row thereof.

Alternatively, metal lines 64 a may be arranged for the upper row andthe lower row of the unit of the PCM patterns 80. Alternatively, metallines 64 b may be arranged for the upper row and the lower row of theunit of the PCM patterns 80.

Accordingly, a part of the metal line 64 a or a part of the metal line64 b having a length corresponding to one row of the PCM patterns 80 isarranged between the opening 2 a and the PCM patterns 80, i.e., in theouter peripheral region 8 c.

A cross section taken along line C-C′ in FIG. 16 and a cross sectiontaken along line D-D′ in FIG. 16 will now be described with reference toFIGS. 17A and 17B.

FIG. 17A is a view showing a cross section taken along line C-C′ in FIG.16.

Referring to FIG. 17A, interlayer insulating films including aninsulating film 16, contact interlayer films 17 and 18, wiringinterlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31,and cover films 32 a and 32 b are provided on a substrate 15 a.

Referring to FIG. 17A, moisture-resistant frame-shaped shields 3composed of wiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f, and 46g, a plug 46 h, a wiring 46 i, all of which are provided in theinterlayer insulating films, are provided in outer peripheral regions 8c each located between an opening 2 a and an element region 8 a.

Referring to FIG. 17A, a part of metal patterns constituting the metalline 64 a and a part of metal patterns constituting the metal line 64 bare disposed not right under the openings 2 a but in the outerperipheral regions 8 c. Furthermore, other parts of the metal patternsconstituting the metal line 64 a, other parts of the metal patternsconstituting the metal line 64 b, and the rectangular patterns 65 a, 65b, and 65 c constituting the PCM patterns 80 are arranged in the scriberegion 8 b.

The metal patterns constituting the metal line 64 a and the metalpatterns constituting the metal line 64 b are formed together with thewiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f, and 46 g. Inaddition, the above metal patterns are formed as wirings by a damasceneprocess. Each of the metal patterns may include a plug portion of thewiring-and-plug 46 a or the like. In such a case, the metal patterns areformed by a dual damascene process, and the metal patterns formed in theinterlayer insulating films are closely in contact with each other viathe plug portions. It is believed that when the metal patterns have thesame structure as that of the wiring-and-plug 46 a and the like, a higheffect of preventing propagation of cracks can be achieved because theadhesiveness between the metal patterns and the interlayer insulatingfilms is high.

The rectangular patterns 65 c of the PCM patterns 80 are made of thesame material as a gate electrode 13. The rectangular patterns 65 c andthe gate electrode 13 are simultaneously formed by the same method as amethod of forming the gate electrode 13. The rectangular patterns 65 aare opening patterns provided inside each of the rectangular patterns 65c. Accordingly, the rectangular patterns 65 a and the gate electrode 13are also simultaneously formed by the same method as the method offorming the gate electrode 13. The rectangular patterns 65 b and an STI10 are simultaneously formed by the same method as a method of formingthe STI 10. That is, the rectangular patterns 65 b are recognized asopening patterns provided in the substrate 15 a.

FIG. 17B is a view showing a cross section taken along line D-D′ in FIG.16.

Referring to FIG. 17B, the interlayer insulating films composed of theinsulating film 16, the contact interlayer films 17 and 18, the wiringinterlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31,and the cover films 32 a and 32 b are provided on the substrate 15 a.

Referring to FIG. 17B, the moisture-resistant frame-shaped shields 3composed of the wiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f, and46 g, the plug 46 h, the wiring 46 i, all of which are provided in theinterlayer films, are provided in the outer peripheral regions 8 c eachlocated between an opening 2 a and an element region 8 a.

However, no patterns are provided in the scribe region 8 b.Specifically, since the PCM patterns 80 are not present, when thesemiconductor devices are cut in the scribe region 8 b with a cuttingblade, cracks are formed at positions distant from themoisture-resistant shield frames 3 or the openings 2 a. Accordingly, apossibility that propagation of cracks reaches the moisture-resistantshield frames 3 or the openings 2 a is low. Therefore, the metal line 64a or the metal line 64 b may not be provided.

As described above, the metal line 64 a and the metal line 64 b arearranged in the outer peripheral region 8 c of the semiconductor deviceof the sixth embodiment so as to be adjacent to the PCM patterns 80.However, unlike the semiconductor devices of the first embodiment to thefifth embodiment, a metal line 2 b surrounding the element region 8 a isnot arranged right under the opening 2 a.

This structure cannot improve an effect of preventing propagation ofcracks over the entire outer peripheral region 8 c. However, by thepresence of the metal patterns constituting the metal line 64 a or 64 b,propagation of cracks can be effectively prevented in areas where cracksare formed with a particularly high probability. This is because theeffect of preventing propagation of cracks due to the presence of themetal patterns constituting the metal line 64 a or 64 b is the same asthat due to the presence of the metal line 2 b described in the firstembodiment to the fifth embodiment.

Alternatively, the metal line 64 a or 64 b can be used in combinationwith the metal line 2 b described in the first embodiment to the fifthembodiment. Such a structure can more strongly prevent propagation ofcracks formed by the presence of the PCM patterns 80.

In the above-described embodiment, the metal line 64 a or 64 b isarranged for the PCM patterns. Alternatively, the metal line 64 a or 64b may be arranged for a pattern that is provided in the scribe region inorder to monitor electrical characteristics of elements.

Seventh Embodiment

In the sixth embodiment, the metal line 64 a or the metal line 64 b iscomposed of isolated metal patterns. In this case, when a metal materialis embedded in the interlayer insulating films to form the metalpatterns by a damascene process, dishing or erosion during a step of CMPoccurs. As a result, a formation failure of the metal patterns mayoccur. Accordingly, in a seventh embodiment, a pattern for preventingthe occurrence of dishing or erosion during a step of CMP is provided soas to be adjacent to the above-mentioned metal patterns.

The seventh embodiment will now be described with reference to FIG. 18.FIG. 18 is a view showing a cross section taken along line C-C′ in FIG.16 in the seventh embodiment.

Referring to FIG. 18, interlayer insulating films composed of aninsulating film 16, contact interlayer films 17 and 18, wiringinterlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31,and cover films 32 a and 32 b are provided on a substrate 15 a.

Referring to FIG. 18, moisture-resistant frame-shaped shields 3 composedof wiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e, 46 f, and 46 g, a plug46 h, a wiring 46 i, all of which are provided in the interlayer films,are provided in outer peripheral regions 8 c each located between anopening 2 a and an element region 8 a.

Referring to FIG. 18, a part of metal patterns constituting a metal line64 a and a part of metal patterns constituting a metal line 64 b arearranged not right under the openings 2 a but in the outer peripheralregions 8 c. Furthermore, other parts of the metal patterns constitutingthe metal line 64 a, other parts of the metal patterns constituting themetal line 64 b, and rectangular patterns 65 a, 65 b, and 65 cconstituting PCM patterns 80 are arranged in a scribe region 8 b.

Referring to FIG. 18, dummy patterns 68 and 69 are arranged so as to beadjacent to the metal line 64 a or the metal line 64 b in the outerperipheral regions 8 c and the scribe region 8 b.

In the above semiconductor device, the metal lines 64 a and 64 b; thesubstrate 15 a; the interlayer insulating films composed of theinsulating film 16, the contact interlayer films 17 and 18, the wiringinterlayer films 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and 31,and cover films 32 a and 32 b; the moisture-resistant frame-shapedshield 3 composed of the wiring-and-plugs 46 a, 46 b, 46 c, 46 d, 46 e,46 f, and 46 g, the plug 46 h, and the wiring 46 i; the opening 2 a; theelement region 8 a; the scribe region 8 b; the outer peripheral region 8c; and the scribe edge 1 are the same as those in the above-describedembodiments.

The dummy pattern 68 include metal patterns provided in the contactinterlayer film 18, the wiring interlayer films 20, 22, 24, 26, 28, and30. The dummy pattern 68 is disposed between the moisture-resistantframe-shaped shield 3 and the metal line 64 a or 64 b. The dummy pattern68 is formed by a damascene process as in the above-described metalpatterns constituting the metal line 64 a or 64 b in the wiringinterlayer films. In this structure, a pattern formation failure causedby dishing or erosion during a step of CMP in the damascene process canbe prevented.

The dummy pattern 69 include metal patterns provided in the contactinterlayer film 18, the wiring interlayer films 20, 22, 24, 26, 28, and30. The dummy pattern 69 is disposed on the PCM patterns 80 between themetal line 64 a and the metal line 64 a or between the metal line 64 band the metal line 64 b. The dummy pattern 69 is formed by a damasceneprocess as in the above-described metal patterns constituting the metalline 64 a or 64 b in the wiring interlayer films. In this structure, apattern formation failure caused by dishing or erosion during a step ofCMP in the damascene process can be prevented.

The term “dishing” refers to a phenomenon in which a metal patternhaving a large width becomes concave so as to have a shallow dish shape.The term “erosion” refers to a phenomenon in which the thickness of aninsulating film disposed in an area where fine metal patterns aredensely arranged decreases together with the thickness of the metalpatterns, as compared with that in an area where wiring patterns are notformed.

Accordingly, in the case where the dummy patterns 68 and 69 are arrangedat appropriate intervals so as to be adjacent to the metal patternsconstituting the metal line 64 a or 64 b, the grinding of the patternsin the step of CMP does not concentrate only on the metal patternsconstituting the metal line 64 a or 64 b. Therefore, a pattern formationfailure can be prevented.

In addition, the semiconductor device of the seventh embodiment alsoprovides the same advantage as that of the semiconductor device of thesixth embodiment. Furthermore, since the dummy pattern 68 is providedbetween the metal line 64 a or 64 b and the moisture-resistantframe-shaped shield 3, this semiconductor device is advantageous in thatpropagation of cracks formed in the scribe region 8 b can be morestrongly suppressed.

Eighth Embodiment

The planar shape of each of the metal patterns constituting the metalline 64 a or 64 b of the sixth embodiment and the seventh embodiment isa rectangle. However, unless the adhesiveness between a metal patternand an interlayer insulating film in which the metal pattern is providedis sufficient, the metal pattern is separated from the interlayerinsulating film, and stress in the interlayer insulating film is nottransferred to the metal pattern. As a result, stress release due toelastic deformation of metal patterns does not occur, and thuspropagation of a crack in interlayer insulating films is not prevented.

Consequently, a metal line of an eighth embodiment has a planar shapehaving irregularities in order to improve the adhesiveness between themetal patterns and the interlayer insulating films.

Planar shapes of a metal line arranged in a semiconductor device of theeighth embodiment will now be described with reference to FIGS. 19A to19G. FIGS. 19A to 19F each show a planer shape of a metal patternforming a metal line 64 a or 64 b.

FIG. 19A shows a basic metal line 70 for a metal pattern forming themetal line 64 a or 64 b. The basic metal line 70 is a rectangularpattern. The metal line 64 a or 64 b is formed by arranging a pluralityof basic metal lines 70 at predetermined intervals. In this structure,the contact area between the metal pattern and an interlayer insulatingfilm in which the metal pattern is provided is increased, compared withthe case where the metal line 64 a or 64 b is formed as a singlepattern. This is because the perimeter of the metal pattern isincreased, and thus, the total area of the side faces of the metalpattern is increased.

FIG. 19B shows a basic metal line 71 for a metal pattern forming themetal line 64 a or 64 b. In the basic metal line 71, smaller rectangularpatterns are arranged in two lines. Accordingly, the contact areabetween the metal pattern and an interlayer insulating film in which themetal pattern is provided is further increased compared with the casewhere the metal line 64 a or 64 b is formed using the basic metal line70.

FIG. 19C shows a basic metal line 72 for a metal pattern forming themetal line 64 a or 64 b. In the basic metal line 72, rectangularpatterns smaller than the small rectangular patterns forming the basicmetal line 71 are arranged in two lines. Accordingly, the contact areabetween the metal pattern and an interlayer insulating film in which themetal pattern is provided is further increased compared with the casewhere the metal line 64 a or 64 b is formed using the basic metal line71.

FIG. 19D shows a basic metal line 73 for a metal pattern forming themetal line 64 a or 64 b. The basic metal line 73 is a metal line inwhich irregularities are provided at the periphery of the basic metalline 70. The perimeter of the basic metal line 73 is increased byproviding the irregularities, thus increasing the contact area betweenthe metal pattern and an interlayer insulating film in which the metalpattern is provided.

FIG. 19E shows a basic metal line 74 for a metal pattern forming themetal line 64 a or 64 b. The basic metal line 74 is a metal line inwhich irregularities larger than the irregularities of the basic metalline 73 are provided at a side of the basic metal line 70. Since theperimeter of the basic metal line 74 is increased, the contact areabetween the metal pattern and an interlayer insulating film in which themetal pattern is provided is increased.

FIG. 19F shows a basic metal line 75 for a metal pattern forming themetal line 64 a or 64 b. In the basic metal line 75, largeirregularities having a pattern shape that extends in the horizontaldirection are provided at the periphery thereof. Since the perimeter ofthe basic metal line 75 is increased, the contact area between the metalpattern and an interlayer insulating film in which the metal pattern isprovided is increased.

FIG. 19G shows a part of the shape of a mask pattern of a mask used forforming the basic metal line 73, 74, or 75.

When the basic metal line 73, 74, or 75 is formed by photolithography,small irregularities of the basic metal line 73, 74, or 75 cannot beformed in some cases because of the following reason. For example, whenthe basic metal line 73, 74, or 75 has small irregularities, light isdiffracted on a mask pattern provided on a mask by the proximity effectof light. As a result, the mask pattern provided on the mask cannot beaccurately transferred on a semiconductor substrate during exposure.

To solve this problem, by providing a recessed portion shown in FIG. 19Gat a corner of the mask pattern corresponding to the basic metal line73, 74, or 75, such small irregularities can be accurately reproduced.This is because the mask pattern is designed in consideration of thediffraction of light.

What is claimed is:
 1. A semiconductor device comprising: a substratethat includes four corners; a semiconductor element formed in a regionof the substrate a first insulating film formed above the substrate; afirst metal line that extends along an edge of the substrate in a planview; a second metal line that extends along the edge of the substratein a plan view; a frame-shaped shield that surrounds the region in aplan view; a second insulating film formed above the first metal lineand the second metal line; and a groove formed in the second insulatingfilm and overlapped with the first metal line in a plan view, whereinthe first metal line is located between the frame-shaped shield and thesecond metal line in a plan view, the first metal line includes aplurality of first wirings and a plurality of first vias, an uppermostwiring of the first wirings is formed in the first insulating film, oneof the first wirings and one of the first vias are formed together of adual damascene structure, the second metal line includes a plurality ofsecond wirings, a plurality of uppermost wirings of the second wiringsis formed in the first insulating film, one of the plurality ofuppermost wirings of the second wirings extends along the edge of thesubstrate in a plan view, and the frame-shaped shield includes aplurality of third wirings.
 2. The semiconductor device according toclaim 1, wherein the frame-shaped shield includes second vias, and oneof the third wirings and one of the second vias are formed together of adual damascene structure.
 3. The semiconductor device according to claim2, further comprising a third insulating film formed above the substrateand located below the first insulating film, wherein the first via, thatis formed of the dual damascene structure, is formed in the thirdinsulating film, and the second via, that is formed of the dualdamascene structure, is formed in the third insulating film.
 4. Thesemiconductor device according to claim 1, wherein a bottom of thegroove is located above the uppermost wiring of the first wirings. 5.The semiconductor device according to claim 4, wherein the bottom of thegroove is located above the uppermost wiring of the third wirings. 6.The semiconductor device according to claim 1, wherein a bottom of thegroove is located apart from the first metal line.
 7. The semiconductordevice according to claim 1, wherein the groove is located between thesecond metal line and the frame-shaped shield in a plan view.
 8. Thesemiconductor device according to claim 1, wherein the groove includesdiscontinuous portions at the four corners in a plan view.
 9. Thesemiconductor device according to claim 1, wherein the second metal lineincludes discontinuous portions at the four corners in a plan view. 10.The semiconductor device according to claim 1, wherein the groove isbent at each of four corners in a plan view.
 11. The semiconductordevice according to claim 10, wherein the groove is bent twice at outerangle of larger than 180 degrees at each of the four corners in a planview, and the groove is bent totally 90 degree at each of the fourcorners in a plan view.
 12. The semiconductor device according to claim1, wherein the first metal line is bent twice at inner angle of largerthan 90 degrees at each of the four corners in a plan view, and thefirst metal line is bent totally at 90 degrees at each of the fourcorners in a plan view.
 13. The semiconductor device according to claim1, wherein the first metal line is connected to the substrate.
 14. Thesemiconductor device according to claim 13, wherein the frame-shapedshield is connected to the substrate.
 15. The semiconductor deviceaccording to claim 1, wherein the first wiring is formed of copper, andthe second wring is formed of copper.
 16. The semiconductor deviceaccording to claim 15, wherein the first wiring includes a first filmlocated between the copper of the first wiring and the first insulatingfilm, the first film includes tantalum, the second wiring includes asecond film located between the copper of the second wiring and thefirst insulating film, and the second film includes tantalum.
 17. Thesemiconductor device according to claim 10, wherein the first metal lineis connected to the substrate.
 18. The semiconductor device according toclaim 17, further comprising a third insulating film formed above thesubstrate and located below the first insulating film, wherein the firstvia, that is formed of the dual damascene structure, is formed in thethird insulating film.